RiteeshGrandhi/sciclaimeval-shared-task huggingface dataset:
Results
The addition of an interfragmentary lag screw to the medially positioned plate increased the initial flexural stiffness by 153% and the shear stiffness by 352%, see Table 2 . The dorsal plate with the lag screw was the stiffest construct ( Figs. 5A , 5B ). Significant differences in stiffness were observed ( p < 0.05, p -values are given in the Supplemental File ) between all pairs of fixation techniques used in the MTP-1 joint arthrodesis. A greater initial flexural stiffness than the flexural stiffness in the range of 5–200 N was observed especially in the constructs with the interfragmentary lag screw. The greatest mean maximum load was obtained for the medially positioned plate ( Table 2 ), but the difference between this group and the dorsal LP lag screw and the medial LP lag screw groups was not significant ( p = 0.70 and p = 0.52, respectively). Results for all samples from the Zwick/Roell machine are available in the dataset ( Daszkiewicz et al., 2022a ).

The greatest relative displacements between bones for the two levels of load were observed for the medial LP group ( Table 3 , Figs. 5C , 5D ). The differences between this group and the dorsal LP lag screw and the medial LP lag screw groups were significant ( p < 0.05, p -values are given in Supplemental File ). A significant decrease of 88% and 80% in the mean transverse displacement was obtained for the medial LP lag screw group compared to the group without the lag screw for the force of 50 and 200 N, respectively. The mean opening displacements were smaller for the dorsal LP lag screw group than for the medial LP lag screw group ( Table 3 ), but these differences were not statistically significant ( Figs. 5C , 5D ). The mean transverse displacement was almost four times smaller than the mean opening displacement in the dorsal LP lag screw group, while 80% greater transverse displacements than the opening displacements were observed for the medial LP specimens for a force of 200 N ( Table 3 ). The displacements of points P1–P3 for the full range of load are available in the dataset ( Daszkiewicz et al., 2022b ).

Note:

The displacements were computed for a force of 50 and 200 N.

The shear fracture of one or two locking screws inserted into the metatarsal bone ( Figure 6A ) was observed between the screw head and shank in the majority of the specimens with the medial plate ( Figure 6F ). The medial LP with lag screw specimens typically failed due to a fracture of the proximal phalanx in the plane of the interfragmentary lag screw insertion ( Figure 6B ) preceded by the fracture of the locking screw ( Figure 6F ). Medial LP and dorsal LP lag screw constructs also failed by fracture of the proximal phalanx in the plane of the most distal locking screw insertion ( Figure 6C ). Fracture of the metatarsal bone in the plane of the locking screws insertion was observed only in the medial LP group ( Figure 6D ). The constructs with the interfragmentary lag screw failed also due to a shear fracture of the metatarsal bone at the steel jig ( Figure 6E ).
Conclusions
The addition of the lag screw to the medially positioned plate significantly increased the shear stiffness in particular and reduced relative displacement between bones for the full load of the MTP-1 joint to the level that should not delay the healing process. Large maximum loads and low values of relative displacement obtained for a force of 50 N suggested that all fixation methods are safe for the partial load of the joint. However, the constructs with the medially positioned plate were less stable compared to the dorsal plate combined with interfragmentary lag screw. It is recommended to use the locking screws with a larger cross-sectional area of the head and plates with a such screw configuration that minimizes the rotation of the plate relative to the metatarsal bone in the medial approach. Further clinical trials are necessary to confirm conclusions obtained with the artificial bone models.
Supplemental Information
Raw data used in the statistical analysis.

Raw data for a force of 50 N and 200 N used in the statistical analysis.
Figure 1: The process of bone samples preparation for arthrodesis in Hypermesh software.

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DOI: 10.7717/peerj.16901/fig-1
Figure 2: Tested fixation constructs in dorsal, plantar, medial and lateral views.
(A) Medial LP. (B) Dorsal LP lag screw. (C) Medial LP lag screw.

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DOI: 10.7717/peerj.16901/fig-2
Figure 3: Dedicated composite jig for the MTP-1 joint arthrodesis.

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DOI: 10.7717/peerj.16901/fig-3
Figure 4: The experimental setup during the bending test.
(A) Overall view. (B) View from the DIC camera with marking the analysis points (P1, P2, P3).

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DOI: 10.7717/peerj.16901/fig-4
Figure 5: Comparison of mean values and standard deviations obtained for different fixation methods.
(A) Flexural stiffness (N/mm). (B) Shear stiffness (N/mm). (C) Relative displacements (mm) between bones for a force of 50 N. (D) Relative displacements (mm) between bones for a force of 200 N. *adjusted p-value < 0.05.

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DOI: 10.7717/peerj.16901/fig-5
Figure 6: Failure modes observed in experimental tests and comparison of maximum loads.
(A) Shear fracture of locking screws inserted into the metatarsal bone. (B) Fracture of the proximal phalanx in the plane of the lag screw insertion. (C) Fracture of the proximal phalanx at the insertion of the most distal locking screw. (D) Fracture of the metatarsal in the plane of the locking screws insertion. (E) Shear fracture of the metatarsal at the fixation site. (F) Maximum loads (N) for different fixation methods. Letters indicate failure mode for each sample. N/A–the failure mode was not identified.

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DOI: 10.7717/peerj.16901/fig-6
Values of parameters used in fused filament fabrication of artificial bone models.
Comparison of mean values of flexural stiffness, initial flexural stiffness, shear stiffness and maximum load, and their standard deviations (SDs) for different fixation methods.
Comparison of mean values of relative displacements between bones and their standard deviations (SDs).